I know someone who does use it and says it's amazing. I'm going to order a system eventually. I had an Eggfinder at one point but that damn thing is too confusing to figure out. I sold it and still plan to get a Featherweight.
Any GPS tracking system has a learning curve that one must master plus it depends upon what one wants to achieve. If one wants to find a rocket and don’t care about data or particulars, any unit that gives a bearing arrow and distance from one’s position will do. If one is interested with live tracking on a map, that takes a bit more work and may require different hardware to achieve.
Live track on a map and you’ll never go back. It was doable before 2007 with with Ham APRS trackers using a Kenwood D7A(g) one wire interfaced with a handheld Garmin mapping GPS. Push the launch button and the received positions are plotted with a breadcrumb trail. Sweet. The Garmin actually will calculate how long it will take one to get to the recovery site at the current walking speed. Really funky. (Don’t buy a used D7A(g) as the TNCs in these units are failing because they are so old. I know as I have two of them that are totally unusable for tracking now.)
It doesn’t take much to punch a 38mm MD rocket up to out of sight range for the entire flight which makes a GPS tracker essential if one wants to get the rocket back (consistently)
I’ve monitored my and others rockets that really got up there and rockets do weird things with the winds aloft. I was able to see that on a livemap that resided in a tracking program on a laptop and of course now there are small tablets that work for this. Rockets go back and forth, spiral every which way and never end up where the crowd is looking by anticipating the ground wind speed and direction. With an APRS tracker the rocket icon was painted on the map along with the altitude and speed next to the breadcrumbed position. Once one uses GPS, they‘ll never go back to RDF unless the size of the rocket precludes the use of a GPS tracker and one is stuck with RDF. Of course a GPS receiver system with a bearing arrow and distance would work for recovery just fine but behavior at altitude (if one is interested in that stuff) is not easily seen unless plotted on a live map.
Nonetheless, choose your system, learn it and practice, practice, practice. Test out a new installation by using a lower powered motor that will keep your GPS tracked rocket in sight in case something goes wrong. At least after an “off nominal” flight you can visually track and get the rocket back to trouble shoot. If all is in order, punch it to however high you want it to go. Kurt